Alternative Names

Causes

Croup is most often caused by viruses such as parainfluenza RSV, measles, adenovirus, and influenza. It tends to appear in children between 3 months and 5 years old, but it can happen at any age. Some children are more likely to get croup and may get it several times. It is most common between October and March, but can occur at any time of the year.

More severe cases of croup may be caused by bacteria. This condition is called bacterial tracheitis.

Croup may also be caused by:

Allergies

Breathing in something that irritates your airway

Acid reflux

Symptoms

The main symptom of croup is a cough that sounds like a seal barking.

Most children will have mild cold symptoms for several days before the barking cough becomes evident. As the cough gets more frequent, the child may have trouble breathing or stridor (a harsh, crowing noise made when breathing in).

Croup is typically much worse at night. It often lasts 5 or 6 nights. The first night or two are most often the worst. Rarely, croup can last for weeks. Talk to your child's health care provider if croup lasts longer than a week or comes back often.

Exams and Tests

Children with croup are most often diagnosed based on the parent's description of the symptoms and a physical exam. Sometimes a provider will listen to a child cough over the phone to identify croup. In a few cases, x-rays or other tests may be needed.

A physical exam may show chest retractions with breathing. When listening to the child's chest through a stethoscope, the health care provider may hear:

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